For 92 minutes Chelsea were at their blunt, wasteful worst. Nicolas Jackson spurned chances and Raheem Sterling missed passes. Axel Disasi advanced from right-back, thought about overlapping and then checked back. Armando Broja spent the evening straying offside and Newcastle led when Benoît Badiashile got confused while trying to dribble away from Callum Wilson. It seemed that Wilson’s early goal would be enough for Newcastle to move on from the disappointment of going out of the Champions League. Instead Eddie Howe was left to stomach more players falling injured and his side enduring a second cup exit in the space of the week. All because Kieran Trippier, normally such a reliable defender, has had a complete systems failure and appears to be in need of a good lie down over the festive period. Perhaps fatigue has affected Trippier, who has already struggled against Everton and Tottenham this month. Chelsea had dominated the second half but were running out of ideas as the final whistle edged closer. They had passed sideways and backwards, making life easy for Newcastle, and Sterling had been booked for diving. It would have been interesting to hear the reaction from the home fans if Newcastle had held on. But sometimes seasons change in the blink of an eye. Out of nowhere, Stamford Bridge went wild when Trippier allowed the Chelsea substitute Mykhailo Mudryk to force a penalty shootout by equalising in the second minute of added time. Mauricio Pochettino erupted, the frustration pouring out of the head coach, and in victory he could praise his side’s display. It was preferable not to dwell on Chelsea’s failings before Mudryk changed the complexion of the entire occasion. Pochettino needed advancing to the semi-finals of the Carabao Cup to spur on his young team. He will note that Stamford Bridge finally sounded united after Djordje Petrovic, making only his second start in goal for Chelsea, sealed a 4-2 win in the shootout by saving Matt Ritchie’s penalty. Trippier, of course, had already sent his spot‑kick wide. Chelsea responded by converting all of their penalties, although the night was not entirely positive. The club and the Metropolitan police are investigating after a home fan invaded the pitch following Mudryk’s goal and appeared to barge Martin Dubravka, Newcastle’s goalkeeper. Newcastle left with grievances. Emil Krafth went off with a gashed shin after being caught by Levi Colwill and Anthony Gordon limped off. Howe also pointed out that Moisés Caicedo could have been sent off for an ugly foul on Gordon during the opening exchanges. The aggression did not intimidate Newcastle, even though they had 11 absentees. Chelsea went close to taking an early lead, Conor Gallagher hitting the bar, but the visitors were up for it. Bruno Guimarães, Lewis Miley and Sean Longstaff were soon dictating the pace in midfield. Newcastle’s desire to pick up the loose balls played a part in them breaking from a Chelsea corner to strike first in the 16th minute. So, too, did a slack pass from Colwill to Caicedo. Wilson seized possession and from there it was a mess. The Newcastle striker was isolated and, although he bundled past Thiago Silva, it seemed the chance had gone when the ball ran away from him. It re-emerged when Badiashile’s error allowed Wilson the chance to dink the ball over Petrovic. Chelsea grew frantic. Sterling shot wide and saw a goalbound effort blocked by Guimarães. Broja came on for the unwell Enzo Fernández. Cole Palmer shot too close to Dubravka. Tempers boiled over when Colwill fouled Krafth. Colwill did not have a good game. Miguel Almirón targeted the left-back, who made way for Malo Gusto at half-time. Even so the game was opening up for Chelsea. Newcastle made changes, Dan Burn and Trippier replacing Krafth and Sven Botman at the back. Then they lost Gordon, who pulled up during a counterattack. Chelsea poured forward. Jackson fired wide. Dubravka thwarted Sterling. There was a roar when Pochettino brought Christopher Nkunku on for a belated debut in the 69th minute. No pressure. It was the £51m forward’s first appearance since injuring a knee in training. Chelsea could not expect too much from him. There were more howls when Sterling overhit a pass to Nkunku. Pochettino thought an attempted clearance from Tino Livramento was going in. Then Gallagher appealed for a penalty when Livramento challenged. No such luck – until Trippier tried to head Gusto’s cross back to Dubravka and Mudryk pounced with a low finish. Chelsea’s momentum surged. Beaten and exhausted, Newcastle felt theirs draining away once again.